The present invention relates to inkjet printheads. In particular, it relates to an optimum heater configuration for a printhead having a tri-color heater chip.
The art of printing images with inkjet technology is relatively well known. In general, an image is produced by emitting ink drops from an inkjet printhead at precise moments such that they impact a print medium, such as a sheet of paper, at a desired location. The printhead is supported by a movable print carriage within a device, such as an inkjet printer, and is caused to reciprocate relative to an advancing print medium and emit ink drops at such times pursuant to commands of a microprocessor or other controller. The timing of the ink drop emissions corresponds to a pattern of pixels of the image being printed. Other than printers, familiar devices incorporating inkjet technology include fax machines, all-in-ones, photo printers, and graphics plotters, to name a few.
A conventional thermal inkjet printhead includes access to a local or remote supply of color or mono ink, a heater chip, a nozzle or orifice plate attached to the heater chip, and an input/output connector, such as a tape automated bond (TAB) circuit, for electrically connecting the heater chip to the printer during use. The heater chip, in turn, typically includes a plurality of thin film resistors or heaters fabricated by deposition, masking and etching techniques on a substrate such as silicon.
To print or emit a single drop of ink, an individual heater is uniquely addressed with a small amount of current to rapidly heat a small volume of ink. This causes the ink to vaporize in a local ink chamber (between the heater and nozzle plate) and be ejected through and projected by the nozzle plate towards the print medium.
As demands for higher resolution and increased printing speed continue, however, heater chips are made with more and denser heater configurations. Thus, heater chip size, fragility, and heat dissipation become implicated with all future designs.
Accordingly, the inkjet printhead arts desire optimum heater configurations supporting relatively small size, high density, chip stability and good heat dissipation properties.
The above-mentioned and other problems become solved by applying the apparatus and method principles and teachings associated with the hereinafter described heater configuration for a tri-color heater chip.
In one embodiment, the heater chip has a substrate with one inner and two outer ink vias adjacently arranged therein. Each ink via has a first and second longitudinal side. A plurality of heaters, formed by thin film layers on the substrate, are grouped together in six rows wherein a first two rows of the six rows are arranged adjacent to the first longitudinal side of one of the two outer ink vias, a second two rows of the six rows are arranged adjacent to either the first or second longitudinal side of the inner via, and a third two rows of the six rows are arranged adjacent to the second longitudinal side of the other of the two outer ink vias. Even further, the first, second, and third two rows each have one row of near heaters and one row of far heaters where the one row of near heaters are closer in distance to their respective ink via in comparison to the one row of far heaters.
In other embodiments, the six rows are staggered, the vertically adjacent heaters are contained in separate rows of the six rows and separated by about {fraction (1/600)}th of an inch, and the near and far heaters are arranged in five groupings of sixteen heaters. During use, up to ten heaters per via can be substantially simultaneously fired in sixteen consecutive firings.
Printheads containing the heater chip and printers containing the printhead are also disclosed.
These and other embodiments, aspects, advantages, and features of the present invention will be set forth in the description which follows, and in part will become apparent to those of ordinary skill in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims.